Getting the Achievement Hands of the Merchandise for 20G means
you kill the Pentagon Thief before he steals your load out. If that
is not easy, YOU
SUCK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Nah
just kiddin. If he is killed with insta kill, you get the
acheivement but no bonfire sale. With bonfire sale activated, you
can pack a punch a weapon for only 1000 points

Easiest way to get the achievement is this.

At the beginning of a PT round, hold a grenade, but do not throw
it. Hold RT on 360, R1 on PS3, and i don't know about PC. Anyways,
just hold it. After a few seconds, you will automatically get
downed. When you are downed, keep shooting the PT with Mustang and
Sally. You will get Max Ammo, and BONFIRE SALE.